Sparking Glass

This is an interesting failed shot. I was shooting a ball bearing at a thick piece of glass (~2 inches thick). The flashes failed, which hasn't happened in a long while.

 

When I fired the air cannon I saw a shower of sparks come from the impact point. Kind of a high tech flint and steel.

 

Anyhow, when I uploaded the photo to look at the impact I could see some structure. I had to raised the exposure a lot to get this view, but it looks like the spark made a pretty fast, very dim flash because I can see the cracks in the glass and they haven't traveled all the way through the glass.

 

And cracks in glass move really fast, many times faster than the projectile velocity.

 

I wish I had some more thick big pieces of glass to try some more.

 

The shatter cone form the shot was also cool. The angle that a shatter cone makes is a function of the velocity of the impact. This impact was higher than my previous marble cannon, so the shatter cone was much more narrow.

 

I may photograph the two cones to show the effect.

 

Cheers.

Done